SIMBAD references

2018MNRAS.476.3290M - Mon. Not. R. Astron. Soc., 476, 3290-3302 (2018/May-3)

WISE J080822.18-644357.3 - a 45 Myr-old accreting M dwarf hosting a primordial disc.

MURPHY S.J., MAMAJEK E.E. and BELL C.P.M.

Abstract (from CDS):

WISE J080822.18-644357.3 (WISE J0808-6443) was recently identified as a new M dwarf debris disc system and a candidate member of the 45 Myr-old Carina association. Given that the strength of its infrared excess (LIR/L* ≃ 0.1) appears to be more consistent with a young protoplanetary disc, we present the first optical spectra of the star and reassess its evolutionary and membership status. We find WISE J0808-6443 to be a Li-rich M5 star with strong H α emission (-125 < EW < -65 Å over 4 epochs) whose strength and broad width are consistent with accretion at a low level (∼10–10 M yr–1) from its disc. The spectral energy distribution of the star is consistent with a primordial disc and is well-fitted using a two-temperature blackbody model with Tinner ≃ 1100 K and Touter ≃ 240 K. AllWISE multi-epoch photometry shows the system exhibits significant variability in the 3.4 and 4.6 µm bands. We calculate an improved proper motion based on archival astrometry, and combined with a new radial velocity, the kinematics of the star are consistent with membership in Carina at a kinematic distance of 90 ± 9 pc. The spectroscopic and photometric data are consistent with WISE J0808-6443 being a ∼0.1 M Classical T-Tauri star and one of the oldest known accreting M-type stars. These results provide further evidence that the upper limit on the lifetimes of gas-rich discs - and hence the time-scales to form and evolve protoplanetary systems - around the lowest mass stars may be longer than previously recognized, or some mechanism may be responsible for regenerating short-lived discs at later stages of pre-main sequence evolution.

Abstract Copyright: © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): stars: fundamental parameters - stars: kinematics and dynamics - stars: pre-main-sequence - open clusters and associations: individual: Carina - solar neighbourhood

Simbad objects: 47

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2019.12.09-21:42:56

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